function [R,err,lambda_n] = explQR(A,m)
% explicit QR-algorithm
%   Input:  A - matrix
%           m - number of iterations
%   Output: R - upper triangular matrix
%           err - velikosti prvku A(n,n-1)
%           lambda_n - aproximace nejmensiho vl.c.

n = size(A,1);
err = [abs(A(n,n-1))];
lambda_n = A(n,n);

for i=1:m,
    [Q,R] = qr(A);
    A = R*Q;
    err = [err,abs(A(n,n-1))];
    lambda_n = [lambda_n, A(n,n)];
end

R=A;